Lb7 ecm or fuel issue.

[Mcraetim23]

I have a 2001 lb7. Just starting having an issue where when its cold outside it will start right up then die a minute or 2 later. When its warm out i have no issue. Thought it was a fuel issue so i replaced fuel filter, all rubber lines and rebuilt filter head. Cp3 is 2 months old and has high flow fuel port bypass.
When it dies i can prime it back up and it starts but dies again no matter how many times i prime it. Found out that when it dies it will start back without priming if it sits a few minutes. Tried checking for dtc since light has been on but scanner wont connect to ecm. Tried hooking up my flashpaq tuner and it does the same thing. Checked all fuses and tried unhooking radio with same results. Im lost, how can it run for a few minutes if ecm is dead and why does it run fine when warm? Any help would be much appreciated! Thanks in advance.

 

[DAVe3283]

First step I'd recommend would be to get the scan tool to connect. Without being able to talk to the ECU it will be much much harder to diagnose. Check the cigarette lighter fuse if you haven't yet.

When it is cold and dies, what if you get a friend to help, and prime it constantly? Will it stay running as long as you're pumping the primer?

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[2004LB7]

may also be a good idea to have your batteries load tested. when you say "cold" what temps are you referring to?

 

[TheBac]

Assuming you do NOT have a lift pump?

 

[Mcraetim23]

First step I'd recommend would be to get the scan tool to connect. Without being able to talk to the ECU it will be much much harder to diagnose. Check the cigarette lighter fuse if you haven't yet.

When it is cold and dies, what if you get a friend to help, and prime it constantly? Will it stay running as long as you're pumping the primer?

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Obd port has power, cigar fuse is good. Priming while running doesn’t prevent it from shutting off. Its running fine today after it warmed up outside.

 

[TheBac]

Could very well be that new CP3 is bad or that bypass is allowing air to get into the system.